5 things to know about a Senate fight over judicial nominees

Will President Obama be allowed to fill three vacant judgeships?That's the fight brewing in the Senate today, as Republicans aim to block the president from filling three vacancies on the D.C. Circuit Court of Appeals. The low-profile fight has huge implications for the balance of power between the president and the Senate, the now routine use of the filibuster and the future of the Supreme Court.Here's five things you need to know about the potential showdown:So what's going on?President Obama …